CN112179188B - Flat plate type loop heat pipe capable of stably running under high heat leakage and using method - Google Patents
Flat plate type loop heat pipe capable of stably running under high heat leakage and using method Download PDFInfo
- Publication number
- CN112179188B CN112179188B CN202011026819.7A CN202011026819A CN112179188B CN 112179188 B CN112179188 B CN 112179188B CN 202011026819 A CN202011026819 A CN 202011026819A CN 112179188 B CN112179188 B CN 112179188B
- Authority
- CN
- China
- Prior art keywords
- steam
- liquid
- ejector
- cavity
- capillary core
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
- F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
- F28D15/0266—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
- F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
- F28D15/0275—Arrangements for coupling heat-pipes together or with other structures, e.g. with base blocks; Heat pipe cores
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
- F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
- F28D15/04—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure
- F28D15/043—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure forming loops, e.g. capillary pumped loops
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Cooling Or The Like Of Electrical Apparatus (AREA)
Abstract
A flat plate loop heat pipe capable of stably running under high heat leakage and a using method thereof comprise an evaporator, an ejector, a main cooler and an auxiliary cooler; the main cooler is connected with an inlet of the evaporator, a liquid outlet of the evaporator is connected with the ejector through the auxiliary cooler, a steam outlet of the evaporator is connected with the ejector, and the ejector connects the main cooler with the evaporator; the evaporator comprises a bottom plate and a top cover; the bottom plate is provided with the top cover, a cavity is formed between the bottom plate and the top cover, and a capillary core is arranged in the cavity; a compensation cavity is arranged between the capillary core and the top cover, and the capillary core is arranged on the upper surface of the bottom plate; the lower surface of the capillary core is provided with a steam channel which is communicated with a steam pipeline. The ejector is added to realize the directional movement of the liquid in the compensation cavity, so that heat leakage can be removed in time, the capillary core is prevented from drying up, the length of the steam pipeline is greatly shortened to reduce flow resistance, and the aims of greatly improving the maximum power of the loop heat pipe and reducing the operating temperature are fulfilled.
Description
Technical Field
The invention belongs to the field of cooling and heat dissipation of electronic components, relates to a heat pipe heat dissipation device, and particularly relates to a flat-plate loop heat pipe capable of stably running under high heat leakage and a use method thereof.
Background
With the rapid development of electronic technology, the heat generation of electronic components is also rapidly increased. The timely and effective dissipation of the heat becomes one of the key technologies in the fields of electronic information and aerospace.
The loop heat pipe is a high-efficiency heat transfer device for realizing heat transfer by utilizing phase change of working media, and has the advantages of no need of consuming external energy, no moving part, long transmission distance and the like. The flat-plate loop heat pipe is convenient to be attached to a heat dissipation object, the wall surface temperature is uniform, and the flat-plate loop heat pipe has great application potential in the fields of space heat management, heat dissipation of ground 5G base stations, CPU/GPU, high-power LED lamps and the like. However, the problem of serious heat leakage from the evaporator to the compensation chamber of the flat-plate loop heat pipe can cause unstable problems such as temperature fluctuation, and the like, thereby greatly limiting the heat transfer performance of the loop heat pipe and the application of the loop heat pipe in a plurality of occasions.
Meanwhile, visual experiments show that bubbles are generated on the upper surface of the capillary core of the high-power lower loop heat pipe, so that heat leakage is further increased, liquid supply of the capillary core by the compensation cavity is hindered, dryness of the capillary core is caused, and the upper power limit of the loop heat pipe is limited. Because the liquid working medium in the compensation cavity in the prior art is basically in a static state, bubbles generated on the upper surface of the capillary core are not easy to separate, and the application of the heat pipe under high power is limited.
Disclosure of Invention
In order to solve the problem that the existing flat-plate loop heat pipe cannot remove heat leakage in time, particularly cannot effectively remove bubbles on the upper surface of a capillary core, the invention aims to provide a flat-plate loop heat pipe capable of stably running under high heat leakage and a using method thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
a flat plate type loop heat pipe capable of stably operating under high heat leakage comprises an evaporator, an ejector, a main cooler and an auxiliary cooler; the main cooler is connected with an inlet of the evaporator, a liquid outlet of the evaporator is connected with the ejector through the auxiliary cooler, a steam outlet of the evaporator is connected with the ejector through a steam pipeline, and the ejector connects the main cooler with the evaporator;
the evaporator comprises a bottom plate and a top cover; the bottom plate is provided with the top cover, a cavity is formed between the bottom plate and the top cover, and a capillary core is arranged in the cavity; a compensation cavity is arranged between the capillary core and the top cover, and the capillary core is arranged on the upper surface of the bottom plate; the lower surface of the capillary core is provided with a steam channel which is communicated with a steam pipeline.
The invention has the further improvement that the height of the steam channel is 0.8-1.2 mm, the width of the steam channel is gradually increased along the length direction close to the steam collecting groove, and the width of the steam channel is gradually increased from 0.3-0.5 mm to 1.5-2 mm;
one side of the steam channel is provided with a steam collecting groove, the steam channel is communicated with the steam collecting groove, and the steam collecting groove is communicated with the steam pipeline.
The invention has the further improvement that the wall surface at one end of the compensation cavity is provided with a working medium inlet, and the wall surface at the other end is provided with a working medium outlet; a working medium inlet of the compensation cavity is connected with the main cooler through a second liquid pipeline, and an outlet of the compensation cavity is connected with the ejector through a third liquid pipeline, an auxiliary cooler and a fourth liquid pipeline in sequence; the second liquid pipeline is connected with a working medium inlet of the compensation cavity; one end of the third liquid pipeline extends into the liquid in the compensation cavity.
The invention has the further improvement that the lower surface of the bottom plate is provided with a mounting groove; a first heat insulation groove is arranged on the periphery of the mounting groove; a second heat insulation groove is arranged between the compensation cavity and the steam collection groove; a first sealing gasket is arranged between the bottom plate and the top cover; the bottom plate is connected with the top cover by bolts; the steam channel closer to the steam collecting groove is wider; and a non-metal second sealing gasket is arranged between the upper surface of the capillary core and the top cover.
The invention is further improved in that the steam pipeline, the second liquid pipeline and the third liquid pipeline are positioned on the same horizontal plane; the second liquid pipeline and the third liquid pipeline are reducer pipes, and the small ends of the second liquid pipeline and the third liquid pipeline are connected with the compensation cavity.
The further improvement of the invention is that the capillary wick is prepared by the following process: filling metal powder into a stainless steel capillary core die and paving the metal powder, putting a cover plate on the metal powder, applying pressure on the cover plate to form the powder, heating the formed powder to 800-plus-one temperature of 1000 ℃ under the protection of argon, preserving the heat for 40 minutes, then cooling to room temperature to obtain a capillary core, and taking out the capillary core; wherein the stainless steel capillary core mould is provided with a bulge corresponding to the steam channel.
The further improvement of the invention is that the metal powder is stainless steel powder, nickel powder, titanium powder or copper powder; the applied pressure is 80-150MPa, and the pressure maintaining time is 10-20 s; the heating and cooling rates are both 5 ℃/min.
The invention has the further improvement that the ejector comprises a steam nozzle, a liquid nozzle and a mixing cavity; wherein, the liquid nozzle is arranged at the periphery of the steam nozzle, and the cavity inlet of the mixing cavity is communicated with the outlets of the steam nozzle and the liquid nozzle.
The invention has the further improvement that the steam nozzle comprises a steam nozzle convergent section, a steam nozzle throat part and a steam nozzle divergent section which are communicated in sequence, and the length of the steam nozzle divergent section does not exceed the diameter of the steam nozzle throat part; the through-flow cross section area of the throat part of the steam nozzle can enable the working medium to reach the sonic velocity at the throat part of the steam nozzle, and the cavity of the mixing cavity is of a gradually-reducing-gradually-expanding structure;
or the steam nozzle comprises a steam nozzle reducing section, and the through-flow sectional area of the outlet of the steam nozzle reducing section is designed according to the working medium flow velocity reaching the sonic speed when the heat dissipation capacity is maximum.
A use method of the flat-plate loop heat pipe capable of stably running under high heat leakage is characterized in that a bottom plate of an evaporator is attached to a heat source, the heat leakage enables the temperature of a compensation cavity to rise, the lower surface of a capillary core starts to evaporate to generate steam after reaching a certain temperature, and the steam enters an ejector through a steam pipeline; the hot liquid/vapor-liquid mixture in the compensation cavity reaches the ejector through the secondary cooler under the action of pressure difference, liquid at the outlet of the ejector reaches the compensation cavity after being cooled by the primary cooler, most of cold liquid flowing into the compensation cavity traverses the compensation cavity under the suction action of the ejector, absorbs heat leakage and takes away bubbles on the upper surface of the capillary core, and then enters the ejector from the outlet of the compensation cavity, and a small part of cold liquid passes through the capillary core to be evaporated under the action of capillary force and gravity, so that efficient heat dissipation of a heat source is realized.
Compared with the prior art, the invention has the following beneficial effects:
according to the invention, the ejector is arranged, so that heat leakage in the compensation cavity and bubbles on the upper surface of the capillary core can be removed in time. The invention utilizes the suction characteristic of the ejector to realize the directional movement of the liquid in the compensation cavity on the premise of not consuming extra energy. The liquid crossing the compensation cavity not only takes away the heat leakage in time and maintains the compensation cavity at a lower temperature, but also has a dragging effect on the generated bubbles to promote the bubbles to separate from the capillary core and flow out of the compensation cavity, thereby ensuring the liquid supply of the capillary core by the compensation cavity. Therefore, the radiator can still maintain stable operation under the conditions of high power and high heat leakage. In addition, the liquid pumped out from the compensation cavity greatly increases the circulating flow speed of the working medium of the heat pipe, and is beneficial to quickly starting the loop heat pipe and fully utilizing the cooler.
The ejector is arranged between the outlet of the evaporator and the inlet of the main cooler, so that the length of a steam pipeline can be greatly shortened, the flowing resistance of working media in the heat pipe is effectively reduced, and the long-distance heat delivery is favorably realized. In the traditional loop heat pipe, a steam pipeline is arranged between an evaporator outlet and a condenser inlet, and the flow velocity of working media in the steam pipeline is far higher than that of a liquid pipeline, so that the pressure loss of the loop heat pipe is concentrated in the steam pipeline. The ejector is introduced to divide a connecting pipeline from the outlet of the evaporator to the inlet of the main cooler into two sections, namely a steam pipeline from the outlet of the evaporator to the ejector and a liquid pipeline from the ejector to the inlet of the main cooler. Because the ejector is close to the outlet of the evaporator, the length of a steam pipeline is greatly shortened, and the flow resistance of the working medium is reduced.
The heat dissipation device has self-adaptive capacity, and can actively adjust the flow rate of liquid in the compensation cavity according to the change of power in the use process to remove heat leakage without manual operation. At high power, as the power is further increased, the amount of heat leakage from the evaporator to the compensation chamber increases, requiring a higher liquid flow rate within the compensation chamber to remove the heat leakage. The steam flow at the outlet of the evaporator also increases with increasing power, the capacity of the ejector to draw liquid increases, and the liquid/vapor-liquid mixture in the compensation chamber is drawn more quickly out into the ejector. Thus, the increased leakage heat can still be removed by the liquid accelerating in the compensation chamber. The ejector is added to realize the directional movement of the liquid in the compensation cavity, so that heat leakage can be removed in time, the capillary core is prevented from drying up, the length of the steam pipeline is greatly shortened to reduce flow resistance, and the aims of greatly improving the maximum power of the loop heat pipe and reducing the operating temperature are fulfilled.
Furthermore, the width of the steam channel which is continuously increased along the steam flowing direction (namely the length direction of the capillary core) is processed on the lower surface of the capillary core, so that the evaporation area is greatly increased, the phase change heat exchange is facilitated, and the steam generated by the liquid evaporation on the lower surface of the capillary core needs to be discharged through the steam channel and enters the steam collecting groove, so that the steam channel is closer to the steam collecting groove, the flow in the steam channel is larger, the steam channel is designed into a channel with the continuously increased width, the change of the flow can be adapted, and the flow resistance is reduced.
Further, since the capillary wick is subjected to a certain degree of volume shrinkage during the sintering process, a fit gap exists between the capillary wick and the evaporator top cover. The non-metal second sealing gasket is arranged between the upper surface of the capillary core and the top cover of the evaporator, so that steam in the steam channel can be prevented from entering the compensation cavity through the matching gap between the capillary core and the top cover, the unstable phenomenon caused by disordered and reverse streaming of steam flow is avoided, and the elastic deformation of the non-metal sealing gasket can be utilized to enable the capillary core to be in close contact with the bottom plate of the evaporator, so that the thermal contact resistance is reduced.
Furthermore, a second heat insulation channel is processed between the steam collection groove and the compensation cavity, and the length of the gradually-expanded section of the steam nozzle does not exceed the diameter of the throat part of the steam nozzle, so that the condensation in the steam nozzle is delayed or even avoided. After the steam enters the steam nozzle of the ejector, the flow is accelerated to expand in the pipe. Since the cooling rate of dry steam is faster than the saturation temperature drop rate during expansion, either too little superheat of the steam or excessive expansion of the steam within the steam nozzle can result in condensation inside the steam nozzle. The steam condensation leads to the increase of the outlet pressure and the reduction of the flow speed of the steam nozzle, thereby not only reducing the liquid suction capacity of the steam-liquid two-phase flow jet pressure boosting device, but also causing the internal flow pulsation of the steam nozzle, and leading the ejector not to operate stably. Considering that the superheat degree of steam at the outlet of the evaporator is low, in order to ensure the stable operation of the heat dissipation device under low power, the invention processes the second heat insulation channel between the steam collection groove and the compensation cavity, increases the heat resistance between the compensation cavity and the steam collection groove, weakens the heat exchange between the low-temperature working medium in the compensation cavity and the high-temperature steam in the steam collection groove, and ensures the superheat degree of the steam at the outlet of the evaporator. In addition, because the position of condensation is usually located in the divergent section of the steam nozzle, the divergent section length of the steam nozzle does not exceed the diameter of the throat part of the steam nozzle, and the condensation in the steam nozzle is delayed or even avoided.
According to the invention, the bottom plate of the evaporator is attached to the heat source, the temperature of the compensation cavity is raised due to heat leakage, the lower surface of the capillary core starts to evaporate to generate steam after reaching a certain temperature, and the steam enters the ejector through the steam pipeline; the hot liquid/vapor-liquid mixture in the compensation cavity reaches the ejector through the secondary cooler under the action of pressure difference, liquid at the outlet of the ejector reaches the compensation cavity after being cooled by the primary cooler, most of cold liquid flowing into the compensation cavity traverses the compensation cavity under the suction action of the ejector, absorbs heat leakage and takes away bubbles on the upper surface of the capillary core, and then enters the ejector from the outlet of the compensation cavity, and a small part of cold liquid passes through the capillary core to be evaporated under the action of capillary force and gravity, so that efficient heat dissipation of a heat source is realized. According to the invention, the ejector is arranged, so that the liquid working medium in the compensation cavity can be sucked, bubbles generated on the upper surface of the capillary core are separated, and the heat dissipation of the heat pipe under high power can be realized.
Drawings
FIG. 1 is a schematic structural diagram of a flat loop heat pipe capable of operating stably under high heat leakage according to the present invention.
Fig. 2 is a sectional view of the evaporator of the present invention, wherein (a) is a sectional view taken along a moving direction of a liquid in a compensation chamber, and (b) is a sectional view taken perpendicular to the moving direction of the liquid in the compensation chamber.
Fig. 3 is a cross-sectional view of an eductor according to the present invention.
FIG. 4 is a startup performance diagram of the present invention.
FIG. 5 shows the power of the loop heat pipe for evaporation and the power of heat leakage under different heating surface powers.
Fig. 6 is a comparison graph of the heat dissipation capacity of the loop heat pipe of the present invention and the loop heat pipe of the conventional structure.
Wherein: 1 is an evaporator; 1-1 is a bottom plate; 1-2 is a capillary core; 1-3 are steam channels; 1-4 are mounting grooves; 1-5 is a first heat insulation groove, 1-6 is a first sealing gasket, 1-7 is a second sealing gasket, and 1-8 is a top cover; 1-9 are compensation cavities; 1-10 is a steam collecting groove; 1-11 is a second heat insulation groove; 2 is a steam pipeline; 3 is an ejector; 3-1 is a steam nozzle; 3-2 is a liquid nozzle; 3-3 is a mixing cavity; 3-41 is a steam nozzle reducing section; 3-5 is steam nozzle throat; 3-6 is a steam nozzle divergent section; 4 is a first liquid pipeline; 5 is a main cooler; 6 is a second liquid pipeline; 7 is a third liquid pipeline; an auxiliary cooler 8; and 9 is a fourth liquid pipeline.
Detailed Description
The invention will be further described with reference to the accompanying drawings.
Referring to fig. 1, the flat plate type loop heat pipe capable of stably operating under high heat leakage mainly comprises an evaporator 1, an ejector 3, a main cooler 5 and an auxiliary cooler 8; wherein, the main cooler 5 links to each other with 1 entry of evaporimeter, and the liquid outlet of evaporimeter 1 links to each other with ejector 3 through side cooler 8, and the steam outlet of evaporimeter 1 links to each other with ejector 3 through steam conduit 2, and ejector 3 links to each other main cooler 5 with evaporimeter 1.
Referring to (a) and (b) in fig. 2, an evaporator 1 is a flat plate evaporator and is composed of a bottom plate 1-1, a capillary wick 1-2, a first sealing gasket 1-6, a second sealing gasket 1-7 and a top cover 1-8; a bottom plate 1-1 of the evaporator 1 is processed by red copper, a top cover 1-8 is arranged on the bottom plate 1-1, and a mounting groove 1-4 with the same size as a heat dissipation object is arranged on the lower surface of the bottom plate 1-1; the periphery of the mounting groove 1-4 is provided with a first heat insulation groove 1-5 for reducing the heat conduction from the periphery of the bottom plate 1-1 to the top cover 1-8; the top cover 1-8 is made of stainless steel or aluminum alloy, and the wall thickness is 1-2 mm; a first sealing gasket 1-6 is arranged between the bottom plate 1-1 and the top cover 1-8, so that not only can the sealing function be realized, but also the direct contact area between the bottom plate 1-1 and the top cover 1-8 is effectively reduced due to the larger width of the sealing gasket, and the heat conduction quantity is further reduced; the bottom plate 1-1 is connected with the top cover 1-8 by bolts; the upper surface of the bottom plate 1-1 is provided with a capillary core 1-2; the lower surface of the capillary core 1-2 is provided with a steam channel 1-3, one side of the steam channel is provided with a steam collecting groove 1-10, the steam channel 1-3 is communicated with the steam collecting groove 1-10, and the steam channel 1-3 which is closer to the steam collecting groove 1-10 is wider, the steam channel is designed into a channel with continuously increased width to adapt to the change of flow, and the flow resistance is reduced. The steam collecting groove 1-10 is connected with a steam nozzle 3-2 of the ejector 3 through a steam pipeline; a second heat insulation groove 1-11 is arranged between the compensation cavity 1-9 and the steam collection groove 1-10, and the second heat insulation groove 1-11 is used for reducing heat transfer between the compensation cavity 1-9 and the steam collection groove 1-10; a nonmetallic second sealing gasket 1-7 is arranged between the upper surface of the capillary core 1-2 and the top cover 1-8; a compensation cavity 1-9 is arranged between the capillary core 1-2 and the top cover 1-8, namely the space between the capillary core 1-2 and the top cover 1-8 forms the compensation cavity 1-9; the wall surface of one end of the compensation cavity 1-9 is provided with a working medium inlet, and the wall surface of the other end is provided with a working medium outlet; working medium inlets of the compensation cavities 1 to 9 are connected with the main cooler 5 through a second liquid pipeline 6, and outlets of the compensation cavities 1 to 9 are connected with liquid nozzles 3 to 2 of the ejector 3 through a third liquid pipeline 7, an auxiliary cooler 8 and a fourth liquid pipeline 9 in sequence; the second liquid pipeline 6 is connected with working medium inlets of the compensation cavities 1-9; one end of the third liquid line 7 extends into the liquid in the compensation chamber 1-9.
In order to reduce the thickness of the evaporator 1, the second liquid pipeline 6 and the third liquid pipeline 7 adopt reducer pipes, and the smaller ends of the second liquid pipeline 6 and the third liquid pipeline 7 are connected with the compensation cavities 1-9; furthermore, the steam pipeline 2, the second liquid pipeline 6 and the third liquid pipeline 7 are located on the same horizontal plane, namely, no height difference exists among the steam pipeline 2, the second liquid pipeline 6 and the third liquid pipeline 7, and therefore the limitation of the pipeline diameter on the height of the evaporator 1 is reduced.
The capillary core 1-2 is formed by sintering metal powder through a capillary core die, and the plurality of rows of steam channels 1-3 are arranged on the lower surface of the capillary core 1-2. The height of the steam channel 1-3 is 0.8-1.2 mm, the width gradually increases along the horizontal direction close to the steam collecting groove 1-10, and gradually increases from 0.3-0.5 mm to 1.5-2 mm. The metal powder is stainless steel powder, nickel powder, titanium powder or copper powder. The inner wall of the bottom plate of the capillary core die is provided with a steam channel 1-3 protrusion with a corresponding shape, a 1-degree drawing slope is arranged to facilitate demoulding, and the steam channel 1-3 is synchronously processed in the process of sintering the capillary core 1-2. The specific sintering process is as follows: and filling metal powder into the stainless steel capillary core die, paving the metal powder, and putting the polished cover plate on the metal powder. Applying 80-150MPa pressure to the cover plate, and keeping the pressure for 10-20s to form the powder. Taking out the formed powder, putting the formed powder into a high-temperature tube furnace, heating the formed powder from room temperature to 800-1000 ℃ at the speed of 5 ℃/min, preserving the heat for 40 minutes, cooling the formed powder to the room temperature at the speed of 5 ℃/min to obtain a capillary core 1-2, and taking out the capillary core 1-2. Argon is introduced into the tube furnace as a protective gas during the sintering process to prevent the sample from being oxidized.
Referring to fig. 3, the ejector 3 is composed of a steam nozzle 3-1, a liquid nozzle 3-2, and a mixing chamber 3-3. The steam nozzle 3-1 is a flow passage of a convergent or convergent-divergent structure. The structure of the flow passage of the steam nozzle 3-1 is selected according to the operation characteristics of the heat radiating object.
For the occasion with relatively stable heat dissipation capacity, a flow channel with a gradually-reducing-gradually-expanding structure is selected, namely the steam nozzle 3-1 comprises a steam nozzle gradually-reducing section 3-4, a steam nozzle throat part 3-5 and a steam nozzle gradually-expanding section 3-6 which are communicated in sequence, and the length of the steam nozzle gradually-expanding section 3-6 does not exceed the diameter of the steam nozzle throat part 3-5. The flow cross-sectional area of the steam nozzle throat 3-5 is designed according to the heat dissipation capacity, so that the working medium can reach the sonic velocity at the point. The flow passage of the structure can ensure that the pressure at the outlet of the steam nozzle 3-1 is lower than the critical pressure ratio, and is more favorable for pumping the liquid/steam-liquid mixture in the compensation cavity 1-9.
And for the occasion with large heat dissipation capacity change, the flow channel with a tapered structure is conveniently selected, namely the steam nozzle 3-1 only comprises a steam nozzle tapered section 3-4, and the flow cross section area of the outlet of the steam nozzle reaches the sonic design according to the working medium flow velocity at the maximum heat dissipation capacity. Although the structure of the steam nozzle 3-1 can not obtain the pressure lower than the critical pressure ratio, the pressure of the steam in the whole steam nozzle can be ensured to be continuously reduced under different heat dissipation amounts, and the stable operation of the ejector 3 is maintained. The liquid nozzles 3-2 are arranged at the periphery of the steam nozzle. The cavity of the mixing cavity 3-3 is a tapered-divergent structure, and the inlet of the mixing cavity is communicated with the outlets of the steam nozzle 3-1 and the liquid nozzle 3-2.
The main cooler 5 and the auxiliary cooler 8 are in a sleeve type water cooling or fin tube type air cooling mode.
The use method of the flat plate type loop heat pipe capable of stably running under high heat leakage is as follows:
the bottom plate 1-1 of the evaporator 1 is attached to a heat dissipation object to increase the temperature, and meanwhile, the temperature of the compensation cavity 1-9 starts to increase due to heat leakage. After reaching a certain temperature, the lower surface of the capillary core 1-2 begins to evaporate to generate steam, and the steam enters the steam collecting groove 1-10 along the steam channel 1-3. Steam in the steam collecting groove 1-10 enters a steam nozzle 3-1 of the ejector 3 through a steam pipeline 2. The steam is accelerated to be depressurized in the steam nozzle 3-1 and forms a low pressure region at the outlet of the steam nozzle 3-1. The hot liquid/vapor-liquid mixture in the compensation chambers 1-9 reaches the ejector 3 through a third liquid pipeline 7, an auxiliary cooler 8 and a fourth liquid pipeline 9 in sequence under the action of pressure difference. Specifically, cold liquid cooled by the secondary cooler 8 enters from the liquid nozzle 3-2 and is subjected to efficient direct contact heat exchange with steam from the steam nozzle 3-1 in the mixing cavity 3-3, so that the steam is completely condensed, and the outlet of the ejector 3 is single-phase liquid. The liquid at the outlet of the ejector 3 is cooled by the main cooler 5 and then reaches the compensation cavities 1-9. Most of cold liquid flowing into the compensation cavities 1-9 traverses the compensation cavities 1-9 under the suction action of the ejector 3, absorbs heat leakage, takes away bubbles on the upper surface of the capillary core, then enters the ejector 3 from the outlets of the compensation cavities 1-9, and only a small part of cold liquid passes through the capillary core 1-2 to be evaporated under the action of capillary force and gravity, so that efficient heat dissipation of a heat source is realized.
Referring to fig. 4, a process of establishing a working medium cycle is described by taking a starting characteristic when the heating surface power is 550W and water are used as working media as an example. The evaporator bottom plate 1 is heated to rise the temperature, steam is generated on the lower surface of the capillary core 1-2 for about 60s and enters the steam pipeline 2, and the temperature of the steam pipeline 2 rises rapidly. The steam yield of about 100s is enough to start the ejector 3, the ejector 3 starts to suck hot liquid/steam-liquid mixture in the compensation cavities 1-9, the temperature of the third liquid pipeline 7 is rapidly increased and then reduced, the ejector 3 is started successfully, the working medium circulation is established, and the heat dissipation device enters a steady-state operation state.
Referring to fig. 5, fig. 5 shows the power for evaporation and the power for heat leakage at different heating surface powers when the loop heat pipe of the present invention is operating stably. The power of heat leakage increases with the increase of the power of the heating surface, and when the power of the heating surface is higher than 450W, the power of heat leakage exceeds 100W and accounts for more than 20 percent of the power of the heating surface. Because the hot liquid in the compensation cavity 1-9 and the vapor bubbles on the upper surface of the capillary core are continuously extracted by the ejector and are supplemented by the low-temperature liquid from the main cooler, the heat leakage in the compensation cavity 1-9 is removed in time, and even if the power of the heat leakage accounts for more than 20% of the power of the heating surface, the loop heat pipe can still stably operate. For the loop heat pipe with the conventional structure, the heat leakage power is controlled to be not more than 10% of the power of the heating surface so as to realize successful starting.
Referring to fig. 6, fig. 6 is a graph comparing the heat dissipation capacity of the loop heat pipe of the present invention and that of the loop heat pipe of the conventional structure. The invention changes the structure of the loop heat pipe, so that the maximum power of the loop heat pipe is increased from 400W to 550W, and the increase amplitude is up to 38%. Meanwhile, the operation temperature is effectively reduced, and the temperature of the bottom plate 1-1 of the evaporator 1 can be reduced by more than 10% under high power. Therefore, the loop heat pipe has excellent heat dissipation performance.
Claims (8)
1. A flat plate type loop heat pipe capable of stably running under high heat leakage is characterized by comprising an evaporator (1), an ejector (3), a main cooler (5) and an auxiliary cooler (8); the main cooler (5) is connected with an inlet of the evaporator (1), a liquid outlet of the evaporator (1) is connected with the ejector (3) through the auxiliary cooler (8), a steam outlet of the evaporator (1) is connected with the ejector (3) through the steam pipeline (2), and the ejector (3) is connected with the main cooler (5) and the evaporator (1);
the evaporator (1) comprises a bottom plate (1-1) and a top cover (1-8); a top cover (1-8) is arranged on the bottom plate (1-1), a cavity is formed between the bottom plate (1-1) and the top cover (1-8), and a capillary core (1-2) is arranged in the cavity; a compensation cavity (1-9) is arranged between the capillary core (1-2) and the top cover (1-8), and the capillary core (1-2) is arranged on the upper surface of the bottom plate (1-1); the lower surface of the capillary core (1-2) is provided with a steam channel (1-3), and the steam channel (1-3) is communicated with the steam pipeline (2);
the wall surface of one end of the compensation cavity (1-9) is provided with a working medium inlet, and the wall surface of the other end is provided with a working medium outlet; working medium inlets of the compensation cavities (1-9) are connected with the main cooler (5) through a second liquid pipeline (6), and outlets of the compensation cavities (1-9) are connected with the ejector (3) through a third liquid pipeline (7), an auxiliary cooler (8) and a fourth liquid pipeline (9) in sequence; the second liquid pipeline (6) is connected with the working medium inlets of the compensation cavities (1-9); one end of the third liquid pipeline (7) extends into the liquid in the compensation cavity (1-9);
the ejector (3) comprises a steam nozzle (3-1), a liquid nozzle (3-2) and a mixing cavity (3-3); wherein, the liquid nozzle (3-2) is arranged at the periphery of the steam nozzle (3-1), and the cavity inlet of the mixing cavity (3-3) is communicated with the steam nozzle (3-1) and the outlet of the liquid nozzle (3-2).
2. The flat-plate loop heat pipe capable of stably operating under high heat leakage according to claim 1, wherein the height of the steam channel (1-3) is 0.8-1.2 mm, the width of the steam channel gradually increases along the length direction close to the steam collecting groove (1-10), and gradually increases from 0.3-0.5 mm to 1.5-2 mm;
one side of the steam channel (1-3) is provided with a steam collecting groove (1-10), the steam channel (1-3) is communicated with the steam collecting groove (1-10), and the steam collecting groove (1-10) is communicated with the steam pipeline (2).
3. The flat-plate loop heat pipe capable of stably operating under high heat leakage according to claim 1, wherein the bottom plate (1-1) is provided at a lower surface thereof with mounting grooves (1-4); a first heat insulation groove (1-5) is arranged at the periphery of the mounting groove (1-4); a second heat insulation groove (1-11) is arranged between the compensation cavity (1-9) and the steam collection groove (1-10); a first sealing gasket (1-6) is arranged between the bottom plate (1-1) and the top cover (1-8); the bottom plate (1-1) is connected with the top cover (1-8) by bolts; the steam channel (1-3) closer to the steam collecting groove (1-10) is wider; a non-metal second sealing gasket (1-7) is arranged between the upper surface of the capillary core (1-2) and the top cover (1-8).
4. A flat-plate loop heat pipe capable of stably operating under high heat leakage according to claim 1, wherein the vapor line (2), the second liquid line (6) and the third liquid line (7) are located on the same horizontal plane; the second liquid pipeline (6) and the third liquid pipeline (7) adopt reducer pipes, and the small ends of the second liquid pipeline (6) and the third liquid pipeline (7) are connected with the compensation cavities (1-9).
5. A flat-plate loop heat pipe capable of stably operating under high heat leakage according to claim 1, wherein the capillary wick (1-2) is obtained by: filling metal powder into a stainless steel capillary core die and paving the metal powder, putting a cover plate on the metal powder, applying pressure on the cover plate to form the powder, heating the formed powder to 800-plus-1000 ℃ under the protection of argon, preserving heat for 40 minutes, then cooling to room temperature to obtain a capillary core (1-2), and taking out the capillary core (1-2); wherein the stainless steel capillary core mould is provided with a bulge corresponding to the steam channel (1-3).
6. The flat plate type loop heat pipe capable of stably operating under high heat leakage according to claim 5, wherein the metal powder is stainless steel powder, nickel powder, titanium powder or copper powder; the applied pressure is 80-150MPa, and the pressure maintaining time is 10-20 s; the heating and cooling rates are both 5 ℃/min.
7. The flat-plate loop heat pipe capable of stably operating under high heat leakage according to claim 1, wherein the steam nozzle (3-1) comprises a steam nozzle tapered section (3-4), a steam nozzle throat (3-5) and a steam nozzle tapered section (3-6) which are communicated in sequence, and the length of the steam nozzle tapered section (3-6) does not exceed the diameter of the steam nozzle throat (3-5); the through-flow cross section area of the steam nozzle throat part (3-5) can enable the working medium to reach the sonic speed at the steam nozzle throat part (3-5), and the cavity of the mixing cavity (3-3) is of a gradually-reducing and gradually-expanding structure;
or the steam nozzle (3-1) comprises a steam nozzle reducing section (3-4), and the through-flow cross section area of the outlet of the steam nozzle reducing section (3-4) is designed according to the working medium flow velocity reaching the sonic speed when the heat dissipation capacity is maximum.
8. A use method of the flat-plate loop heat pipe capable of stably operating under high heat leakage according to any one of claims 1 to 7, characterized in that a bottom plate (1-1) of the evaporator (1) is attached to a heat source, the heat leakage enables the temperature of the compensation cavity (1-9) to rise, after a certain temperature is reached, the lower surface of the capillary core (1-2) starts to evaporate to generate steam, and the steam enters the ejector (3) through the steam pipeline (2); hot liquid/vapor-liquid mixture in the compensation cavity (1-9) reaches the ejector (3) through the secondary cooler (8) under the action of pressure difference, liquid at the outlet of the ejector (3) is cooled through the main cooler (5) and then reaches the compensation cavity (1-9), most cold liquid flowing into the compensation cavity (1-9) traverses the compensation cavity (1-9) under the suction action of the ejector (3), absorbs heat leakage and takes away bubbles on the upper surface of the capillary core, then enters the ejector (3) from the outlet of the compensation cavity (1-9), and a small part of cold liquid passes through the capillary core (1-2) to be evaporated under the action of capillary force and gravity, so that efficient heat dissipation of a heat source is realized.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011026819.7A CN112179188B (en) | 2020-09-25 | 2020-09-25 | Flat plate type loop heat pipe capable of stably running under high heat leakage and using method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011026819.7A CN112179188B (en) | 2020-09-25 | 2020-09-25 | Flat plate type loop heat pipe capable of stably running under high heat leakage and using method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112179188A CN112179188A (en) | 2021-01-05 |
| CN112179188B true CN112179188B (en) | 2021-08-13 |
Family
ID=73944876
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011026819.7A Active CN112179188B (en) | 2020-09-25 | 2020-09-25 | Flat plate type loop heat pipe capable of stably running under high heat leakage and using method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112179188B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112923577A (en) * | 2021-01-12 | 2021-06-08 | 西安交通大学 | Light-concentrating solar heat collection system based on loop heat pipe |
| CN114295399B (en) * | 2021-12-29 | 2023-09-01 | 上海交通大学 | Visual testing device for heat dissipation performance of vapor chamber evaporator |
| CN115235274A (en) * | 2022-06-13 | 2022-10-25 | 山东格熵热能科技有限公司 | Flat-plate loop heat pipe evaporator for chip radiator |
| CN115307469B (en) * | 2022-08-09 | 2024-03-22 | 西安交通大学 | Multi-source driven high-power loop heat pipe radiating device |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003194485A (en) * | 2001-12-27 | 2003-07-09 | Mitsubishi Electric Corp | Evaporator, loop heat pipe with built-in reservoir, and heat transport method |
| CN101936309A (en) * | 2009-07-01 | 2011-01-05 | 洛阳蓝海实业有限公司 | Two-phase flow jet-type boosting heat exchanger |
| CN104930893A (en) * | 2015-05-29 | 2015-09-23 | 西安交通大学 | Ejector assisted slab-type loop heat pipe |
| CN108317878A (en) * | 2017-01-16 | 2018-07-24 | 北京空间飞行器总体设计部 | A kind of loop heat pipe evaporator |
| CN109855456A (en) * | 2019-03-12 | 2019-06-07 | 西安交通大学 | A kind of loop heat pipe radiator having stream-liquid two-phase flow injection increasing apparatus |
| CN110267485A (en) * | 2019-05-27 | 2019-09-20 | 西安交通大学 | A kind of evaporation-boiling capillary wick coupling fluid infusion capillary wick composite structure |
| CN110530185A (en) * | 2019-08-20 | 2019-12-03 | 西安交通大学 | A kind of micro-structure liquid self-propelled plates formula loop circuit heat pipe with branch |
-
2020
- 2020-09-25 CN CN202011026819.7A patent/CN112179188B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003194485A (en) * | 2001-12-27 | 2003-07-09 | Mitsubishi Electric Corp | Evaporator, loop heat pipe with built-in reservoir, and heat transport method |
| CN101936309A (en) * | 2009-07-01 | 2011-01-05 | 洛阳蓝海实业有限公司 | Two-phase flow jet-type boosting heat exchanger |
| CN104930893A (en) * | 2015-05-29 | 2015-09-23 | 西安交通大学 | Ejector assisted slab-type loop heat pipe |
| CN108317878A (en) * | 2017-01-16 | 2018-07-24 | 北京空间飞行器总体设计部 | A kind of loop heat pipe evaporator |
| CN109855456A (en) * | 2019-03-12 | 2019-06-07 | 西安交通大学 | A kind of loop heat pipe radiator having stream-liquid two-phase flow injection increasing apparatus |
| CN110267485A (en) * | 2019-05-27 | 2019-09-20 | 西安交通大学 | A kind of evaporation-boiling capillary wick coupling fluid infusion capillary wick composite structure |
| CN110530185A (en) * | 2019-08-20 | 2019-12-03 | 西安交通大学 | A kind of micro-structure liquid self-propelled plates formula loop circuit heat pipe with branch |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112179188A (en) | 2021-01-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112179188B (en) | Flat plate type loop heat pipe capable of stably running under high heat leakage and using method | |
| CN105403085B (en) | Variable element liquid-sucking core ultrathin heat pipe | |
| CN112201635B (en) | Phase-change heat dissipation device and method for high-heat-flux chip driven cooperatively | |
| CN201383909Y (en) | Micro-channel cold plate device for liquid cooling radiator | |
| CN201834905U (en) | White spirit distilling and cooling device | |
| CN104880107B (en) | A kind of follow-on ultra-thin loop circuit heat pipe | |
| CN112113450A (en) | Oscillation composite capillary core soaking plate structure for aerospace electronic heat dissipation | |
| CN112179190A (en) | Ultrathin flat-plate loop heat pipe of coupling ejector | |
| CN100344918C (en) | Dedicated evaporation cavity of semiconductor electronic refrigerator, and preparation method | |
| CN113357946B (en) | Self-driven thermosiphon loop heat dissipation device of coupled gas-liquid two-phase flow ejector pump | |
| CN112696961B (en) | Three-stage phase change heat exchanger | |
| CN116631734A (en) | Efficient heat dissipation oil immersed transformer | |
| WO2023035574A1 (en) | Loop heat pipe-based heat dissipation device | |
| CN113309684B (en) | Variable-heat-conductivity-coefficient liquid metal cooler in vacuum environment | |
| CN115406279A (en) | Method for controlling rapid reduction of liquid level in two evaporators | |
| CN210218248U (en) | Water-saving and energy-saving type water jet air extractor system | |
| CN206698562U (en) | A kind of rapid heat radiation device for power equipment | |
| CN217383842U (en) | Vacuum pumping system | |
| CN100470171C (en) | Tiny channel aluminum strip tubular mode heat pump type heat exchanger of air conditioner / air conditioning machinery | |
| CN207365538U (en) | A kind of freezing exchange system for slurries cooling | |
| CN217433018U (en) | Novel indium strip solidification forming device | |
| CN107144051A (en) | A kind of high efficiency condenser | |
| CN217979432U (en) | Refrigerating system applied to air-cooled refrigerator | |
| CN217602871U (en) | Air compressor machine circulative cooling device | |
| CN219977210U (en) | Energy-saving heat exchanger tube box |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |